Subcritical Delamination in Epoxy Bonds to Silicon and Glass Adherends: Effect of Temperature and Preconditioning

The effects of temperature and preconditioning in deionized (DI) water and a cyan ink vehicle used in inkjet printer cartridges on the durability of glass/epoxy and silicon/epoxy systems have been investigated. A test matrix consisting of test temperatures, preconditioning temperatures, preconditioning times, and nature of adherends and adhesives was developed and a series of experiments was conducted using wedge test specimens (glass or silicon coupons bonded with epoxy) to investigate the subcritical adhesion performance of the glass/epoxy and silicon/epoxy interfaces. The glass/epoxy and silicon/epoxy interfaces were found to be relatively insensitive to temperature over a range of 22-60 degrees, but significant temperature effects, more complex than suggested by time-temperature superposition (TTSP), were observed above 60 degrees C, depending on the environmental chemistry and nature of the adhesive used.Specimens made of silicon coupons bonded with epoxy were subjected to preconditioning in DI water and the cyan ink vehicle prior to wedge insertion to study the effect of prior environmental exposure. The wedge test data from preconditioned specimens were compared with standard wedge test results and the Si/epoxy interface was found to be insensitive to preconditioning in DI water but was affected significantly by preconditioning in the cyan ink vehicle. Plots of crack velocity versus applied strain energy release rate for particular sets of environmental conditions are presented and a comparison is made for different environmental conditions to quantify the subcritical debonding behavior of systems studied.